Viewing angle system for backlighted displays

ABSTRACT

An apparatus to widen the light dispersion pattern of a light source shining through an overlay window from the viewing side of an electrical computer system. The overlay window is coupled to a panel of the system. The overlay window includes a transparent material, which has a first surface facing the light source and a second surface facing away from the light source to define a viewing side. An opaque material can be disposed on the first surface to partially cover the first surface to form a viewing window. A first diffusing mechanism is disposed on the first surface, and a second diffusing mechanism is disposed on the second surface. In response to the passage of the light output through the viewing window, the light dispersion pattern of the light output from the viewing side of the overlay window has a viewing angle of up to about 180 degrees.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/301,352 filed Nov. 21, 2011, which is herebyincorporated by reference to its entirety herein.

FIELD

The present disclosure relates to backlighted displays, and inparticular, to backlighted displays with an increased viewing angle fromthe viewing side of the panel.

BACKGROUND

Displays have a clear window to allow light transmission from a lightsource for customer identification of activity. For example, the lightsource can be a light pipe, which is a clear plastic part that conveyslight indirectly from one source location to another, or directly from alight emitting diode (LED) source. In the context of electronicequipment, manufacturers commonly use LEDs mounted on circuit boards totransmit light to front panels or faceplates through display windowsthat are viewable by users of the electronic equipment. Accordingly, themanufacturers can enable the users to obtain useful visual informationdirectly from the LEDs of the circuit boards even if the LEDs arenestled deeply behind the front panels or faceplates.

The problem is that the LED can be mounted a considerable distance fromthe back of the display window, such that at certain viewing angles fromthe front of the display window, the LED becomes less visible or appearsto have shadows. For instance, when the end user is looking at thedisplay window from the side (i.e., not dead on) within blind spots ofthe light or about 45 degrees relative to the planar surface, the visualinformation about the system will not be apparent to the end user.Shadowing at the display window can reduce the effective area of thedisplay window and make alphanumeric elements or logos or designs lessappreciable. It has been conventional to overcome the shadowing aspectsby shortening the distance between the LED and display window, whichreduces the viewing angle. In addition, it has been conventional to usea light source larger than the display window, which is a more expensivecomponent to procure and operate and takes additional space within theelectronic component. Furthermore, light pipe configurations areproblematic because a light pipe is easily mounted out of alignment. Inaddition, the light pipe provides an unbalanced intensity throughout thelight pipe because of the poor internal reflection of the light pipealong the light pipe path. Furthermore, the light pipe is mountedextremely close to the display window (e.g., about 0.020 inches), and istypically sized much larger than the display window to avoid shadowing.

Thus, there remains a need for a system having a display windowbacklighted with a light source, which has a wider viewing angle so theend user can obtain useful visual information about the system from thelight source from the sides of the front panel or faceplate. It would bedesirable to provide a display window with a more evenly distributedlight across the window and/or with reduced shadowing.

BRIEF DESCRIPTION OF THE DRAWINGS

The components and the figures are not necessarily to scale, emphasisinstead being placed upon illustrating the principles of the exampleembodiments. Moreover, in the figures, like-referenced numeralsdesignate corresponding parts throughout the different views.

FIG. 1 is a perspective view of one embodiment of an electronic computersystem;

FIG. 2 is a perspective view of one embodiment of an electronic modulehaving one example of a display assembly;

FIG. 3 is a front view of the module of FIG. 2;

FIG. 4 is a side view of one example of a display assembly;

FIG. 5 is a cross-sectional view of an example overlay window;

FIG. 6 is a cross-sectional view of another example of an overlaywindow;

FIG. 7 is a cross-sectional view of another example of an overlaywindow; and

FIG. 8 is a cross-sectional view of another example of a displayassembly.

DETAILED DESCRIPTION OF THE DRAWINGS Overview

In one embodiment, an apparatus may include an electronic computersystem having a panel. The apparatus also may include a light sourceconfigured to generate a light output. An overlay window may be coupledto the panel of the electronic computer system. The overlay window mayinclude a transparent material having a first surface facing the lightsource and a second surface facing away from the light source to definea viewing side of the overlay window. An opaque material may be disposedon the first surface. The opaque material may partially cover the firstsurface to define an uncovered surface area forming a viewing window. Afirst diffusing mechanism may be disposed on the first surface along theuncovered surface area. A second diffusing mechanism may be disposed ona portion of the second surface corresponding to the viewing window. Thelight output may have a first dispersion angle at the first surface ofthe overlay window and a wider dispersion angle at the second surface ofthe overlay window so that a viewing angle of the light output from theviewing side of the overlay window is up to about 180 degrees.

In another embodiment, a system may include an electronic computersystem having a panel. The system also may include a light sourceconfigured to generate a light output having a first dispersion angle.An overlay window may be coupled to the panel of the system. The overlaywindow may include a transparent material. The transparent material mayhave a first surface facing the light source and a second surface facingaway from the light source to define a viewing side of the overlaywindow. A translucent ink may be disposed on the first surface along aregion of the overlay window defining a viewing window. A plurality ofsurface irregularities may be formed in a portion of the second surfacecorresponding to the viewing window. In response to the passage of thelight output through the viewing window, a viewing angle of the lightoutput from the viewing side of the overlay window may be up to about180 degrees.

In yet another embodiment, a method may include providing an electricalcomputer system having a panel and a light source configured to generatea light output. The method also may include providing an overlay windowcoupled to the panel of the system. The overlay window may include atransparent material having a first surface facing the light source anda second surface facing away from the light source to define a viewingside of the overlay window. An opaque material may be disposed on thefirst surface of the transparent material. The opaque material maypartially cover the first surface to define an uncovered surface areaforming a viewing window. A first diffusing mechanism may be disposed onthe first surface along the uncovered surface area. A second diffusingmechanism may be disposed on a portion of the second surfacecorresponding to the viewing window. The method also may includegenerating a light output having a first dispersion angle toward theoverlay window. The method also may include scattering the light outputwith the first diffusing mechanism at a second dispersion angle that isgreater than the first dispersion angle. The method also may includescattering the light output with the second diffusing mechanism at athird dispersion angle that is greater than the second dispersion angle.In response to the passage of the light output through the viewingwindow, a viewing angle of the light output from the viewing side of theoverlay window is up to about 180 degrees.

Example Embodiments

The following description generally relates to apparatus and methods forwidening the light dispersion pattern of a light source through adisplay window of an electronic computer system to a viewing angle of upto 180 degrees. The electronic computer systems can be for a variety ofindustry applications, such as, e.g., telecommunication network serversystems, web server systems, LAN application and file server systems,personal computer systems, and vehicle control systems.

FIG. 1 illustrates a perspective view of one embodiment of an electroniccomputer system. The electronic computer system can be any computerequipment such as a computer server, a router, a switch, a blade server,or any other computing device. One exemplary electronic computer systemthe CISCO CATALYST 3750X and 3560X switches, which are commerciallyavailable from Cisco Systems Inc. (San Jose, Calif.). The electroniccomputer system 100 may include a chassis 104. The chassis 104 can forma box shape with a face panel 106, a rear panel opposite the face panel,a pair of side panels 108 (only one shown), a base panel 110, and a toppanel 111 opposite the base panel 110. The terms “face,” “rear,” “side,”“base,” and “top,” and derivatives thereof relate to the orientation ofthe component as shown in the figures, and it is understood that theseterms are illustrative and that the component in the figures can assumealternative orientations. The system 100 can be a rack-mounted unit fora computer server rack, which is typically sized to dimensionalstandards as set forth by the Electronic Industries Alliance (EIA). TheEIA has defined the mounting equipment in terms of a rack unit (RU),where each RU is 44.45 mm (1.75 inches) in height and 480 mm (19 inches)or 580 mm (23 inches) in width. The system 100 includes one or moredisplay assemblies 200 provided on one or more panels, such as the frontpanel 120 of an electronic module 125 as shown in FIG. 1. The displayassembly 200 can be configured to provide useful visual information toan end user, e.g., about the condition or status of the system 100 or acomponent of the system 100, such as the module 125.

FIGS. 2-4 depict a close up view of the display assembly 200. The visualinformation provided by the display assembly 200 can be directed to aviewing side 205 that is external to the system 100. The displayassembly 200 can include an overlay 210 and a light source 215. In oneexample, the overlay 210 is attached to a recessed area in the surfaceof the panel 106 such as into a bezel.

The overlay 210 can have a first surface 220 shown facing the lightsource 215 and a second surface 222 facing away from the light source orfacing the viewing side 205. The overlay 210 can be formed from a planarsheet of a light transmitting material, having various sizes such asabout 1 inch×17 inches×0.020 inches of a material, although other sizesmay be used. Such light transmitting material can include a polymer suchas a polycarbonate resin thermoplastic sold under the trademark LEXAN.The overlay 210 can be transparent or clear. In one example, the overlaymay be tinted with a color. In one example, the overlay is a sheet ofmaterial that is about 0.020 inches thick, although the thickness can beless or more depending on the application.

In FIG. 4, the light source 215 can be provided along an axis X, whichcan be oriented substantially perpendicular to the overlay 210, but canvary up to about 5 degrees for manufacturing tolerances. The lightsource 215 can be electrically coupled to a circuit board, and is spacedby a distance 225 from the first surface 220 of the overlay 210. In oneexample, the distance 225 is about 1.59 mm (0.0625 inches). The lightsource 215 can include one or more of the following: incandescent bulbs,fluorescent bulbs, light emitting diodes (LEDs), or other types of lightsources used in electronic equipment. In one example, the light source215 is one or more LEDs. In one non-limiting example, the light sourceincludes a LED (2.1 volt, 3 mm diameter, and a luminous intensity-green6.3 and yellow-4.3), although other sizes, voltages, luminous intensityand colors may be used. The light source 215 provides an illuminationdiameter d1 at the first surface of the overlay, which can be determinedby the light dispersion half-angle y relative to the axis X and thedistance 225.

In the figures, the display assembly 200 can include an opaque material240 to substantially block light generated by the light source 215. Inone example, the opaque material 240 can be disposed on the firstsurface 220 of the overlay 210 to partially cover the first surface 220in a manner to define one or more areas of exposed or uncovered surfaceareas 242. For example, the opaque material 240 can define the border ofthe exposed surface area 242 in order to form a discrete viewing window246, as shown in FIGS. 2-3, where the light source shines through. Inone example, the opaque material can be applied in a manner to definethe viewing window 246 with a variety of shapes, such as circular,elliptical, rectangular, or other geometric shapes. In another example,the shape of the viewing window 246 can be virtually any shape, such asthe shape of a logo or trademark or letters and/or numbers. One or moreviewing windows (e.g., six viewing windows shown in FIG. 3, viewingwindows 246A, 246B, 246C, 246D, 246E, and 246F, which have the shapes ofletters and numbers and a rectangular box) may be provided with theoverlay 210. Each viewing window may be associated with a single lightsource such as a single LED or with more than one light source such as aseries of LEDs.

The opaque material 240 can include an opaque polymer, metal, film,tissue, or coating, of one of more colors, which can be attached to asurface of the overlay 210. In one example, the opaque material includesan opaque ink that can be sprayed, dipped, brushed, silkscreened, orotherwise coated on the overlay. The opaque ink coating can have athickness of about 0.002-0.003 inches, although the thickness can beless or more. The opaque color can be selected by the manufacturer.

The light dispersion half angle y and the distance 225 of the lightsource 215 are selected to define a first illumination diameter d1. Inone example, the diameter d1 can be sized larger than the viewing window246 such that light generated by the light source 215 is transmitted atleast partially to the opaque material 240. In another example, thediameter d1 may be smaller that the viewing window. To this end, thedisplay assembly 200 generates a light dispersion pattern having a firstviewing angle A1 from the viewing side 205 that is generally less thanabout ninety degrees when the light source 215 has the firstillumination diameter d1. The light dispersion pattern with the firstviewing angle A1 can be at least twice the angle of the light dispersionhalf-angle γ.

The display assembly 200 can include a diffusing mechanism 250 that isconfigured to at least partially scatter light generated by the lightsource 215 so that light output of the overlay 210 from the viewing side205 has a wider light dispersion pattern. The diffusing mechanism 250can be provided on the entire or selected areas of one or both of thefirst and second surfaces 220, 222 of the overlay 210. Nonlimitingexamples of the diffusing mechanism 250 include one or more of thefollowing: a paint coating or pattern, a film, an etched pattern, amachined pattern, an ink or printed coating or pattern, a hot stampedpattern, or a molded pattern. The light output of the overlay 210 fromthe viewing side 205 can be controlled for a desired light dispersionpattern by varying the density, opaqueness or translucence, shape,depth, color, area, index of refraction, or type of surfaceirregularities on one or more selected areas of the overlay surfaces.

In one example, a first diffusing mechanism 250A of the diffusingmechanism 250 can be disposed on a surface of the overlay, such as,e.g., the first surface 220 to at least partially cover the uncoveredsurface area 242, such as shown in FIG. 5. For example, the firstdiffusing mechanism 250A can cover the entire inner side of the viewingwindow 246 so that the surface area 242 is no longer exposed oruncovered or selected areas of the viewing window such as to form, e.g.,a design or lettering. In one example, the first diffusing mechanism250A can include a translucent polymer, film, coating, or ink. Forexample, the first diffusing mechanism 250A can include a translucentink coating having a thickness of about 0.002-0.003 inches, although thethickness can be less or more to vary the diffusing effects. The ink maybe applied for example by pad printing, silk screening, ink jet, or heattransfer film process or other ink processes known in the art. In oneexample, the first diffusing mechanism 250A such as the translucent inkcan form a variety of designs, patterns, or shapes, such as letters,numbers, etc. For example, the letters can spell the name of amanufacturer, model, or other desired word(s). The translucent ink canbe sized to cover the entire viewing window.

In another example, the first diffusing mechanism 250A can include asurface of the overlay 210 having surface irregularities 255 to causethe light generated by the light source 215 to scatter at a wider lightdispersion pattern. For example, the surface, such as, e.g., the secondsurface 222, of the overlay 210 can be textured in a manner such thatthe surface has surface irregularities 255. At least a portion of therespective surface corresponding to the viewing window 246 can have thesurface irregularities, although the entire surface may be provided withthe surface irregularities. The surface irregularities 255 can providethe surface with a change in geometry such as a uniform or randompattern of low spots and/or high spots. The surface irregularities 255can be formed by a variety of processes, such as a laser, an abrasivedevice such as sand paper, chemical etching, or other processes known inthe art. For example, the surface irregularities 255 can be formed inaccordance with a visual texture standard provided by Mold-Tech(division of Roehlen Industries), such as MT-11000 (0.0004-inch deepfine texture), MT-11010 (0.001-inch deep texture), MT-11020 (0.0015-inchdeep texture), and MT-11030 (0.002-inch deep texture).

The first diffusing mechanism 250A can provide an opacity in the rangeof about 20% to about 80%, preferably about 50% to about 70%, and morepreferably about 60%, although it can be outside the ranges if sodesired. It is recognized that a lower opacity can increase theintensity, but reduce the dispersion of the light output of the lightsource through the overlay, and the opposite is also true where a higheropacity can reduce the intensity, but increase the dispersion. To thisend, the display assembly 200 with the first diffusing mechanism 250Acan generate a wider light dispersion pattern having a second viewingangle A2, larger than the first viewing angle A1, from the viewing sidethat is generally less than about 150 degrees to about 170 degrees whenthe light source 215 has the first illumination diameter d1.

In one example, the display assembly 200 can include a second diffusingmechanism 260 of the diffusing mechanism 250, in addition to the firstdiffusing mechanism 250A, as shown in FIG. 6. Here, the first diffusingmechanism 250A is associated with the first surface of the overlay 210and the second diffusing mechanism 260 is associated with the secondsurface of the overlay 210. To this end, the first and second diffusingmechanisms 250A, 260 can be separated by the thickness of the overlay210. The first diffusing mechanism 250A can at least partially scatterthe light generated by the light source 215 at the first surface at alarger angle. The second diffusing mechanism 260 can at least partiallyscatter the previously scattered light from the first diffusingmechanism 250A at the second surface at even a larger angle than thefirst diffusing mechanism. The second diffusing mechanism can scatterthe light output at the second surface of the overlay and behind thesecond surface for two scattering effects.

To this end, the display assembly 200 with the first and seconddiffusing mechanisms 250A, 260 can generate an even wider lightdispersion pattern having a third viewing angle A3. The third viewingangle A3 can be larger than the first and second viewing angles A1, A2,as seen from the viewing side 205, which can be generally in the rangeof about 170 degrees up to about 180 degrees when the light source 215has the first illumination diameter d1. To this end, an end user can bepositioned along the panel and is capable of seeing the informationconveyed by the light source, without having to be directly in front ofthe viewing window. This arrangement can allow the end user to view froman aisle of computer racks the status or condition of the system, ratherthan in front of each viewing window. It should be noted that thedisplay assembly 200 may have different light dispersion patterns withmore than one viewing angle. For example, when a first area of theoverlay does not include the first diffusion mechanism, and a secondarea of the overlay includes the first diffusion mechanism, lightthrough the second area will have a wider light dispersion pattern thanthe light through the first area. The three viewing angles, A1-A3, shownin FIG. 4 are for illustrative purposes to show the relative ranges ofthe viewing angles.

In one example, the display assembly 200 may include one or moreembossments 265 (four shown) to offset a portion of the overlay from thegenerally planar portion, as shown in FIG. 7. The embossments 265 areformed in the overlay 210 and may generally extend toward the viewingside 205, although at least one embossment may be formed to extendtoward the light source. The embossments 265 may form a variety ofdesigns, patterns, or shapes, such as letters, numbers, etc. Forexample, the letters can spell the name of a manufacturer, model, orother desired word(s). The embossments 265 can be formed by a variety ofprocesses known in the art, such as with a tool and heat-vacuum formedprocess. In one example, the tool used for embossment may have atextured pattern thereon, such that during the embossing process, atextured surface 260 is formed on the embossments 265 of the overlay.FIG. 7 depicts an exemplary display assembly 200 having the firstdiffusing mechanism 250A, the second diffusing mechanism 260, and theembossment 265 applied to the overlay 210. The viewing angle for suchassembly can be up to 180 degrees.

FIG. 8 illustrates another display assembly 300 having a light source315, such as a LED, and a light pipe 320. The light output from thelight source is transmitted through the light pipe 320 toward theviewing window 246 formed in the overlay 210.

In one method of manufacturing, a sheet of overlay material is cut tothe desired size. A first opaque ink color can be applied, such assilkscreened, to the first surface of the overlay, such as to form alogo or model number information. A second opaque ink color, differentthan the first ink color, such as a lighter color, can be applied, suchas silkscreened, to the entire first surface of the overlay, except forthose areas which are to be left exposed. For example, the second opaqueink can outline the shapes, numbers, or letters of the viewing window. Atranslucent ink can be applied, such as silkscreened, to exposed areas.The second surface of the overlay can be textured on the opposite sidesof where the translucent ink is applied. Embossments may be formed inthe overlay.

Various embodiments described herein can be used alone or in combinationwith one another. The foregoing detailed description has described onlya few of the many possible implementations of the present invention. Forthis reason, this detailed description is intended by way ofillustration, and not by way of limitation.

1.-20. (canceled)
 21. An apparatus comprising: a display assembly for anelectrical module housing, the display assembly comprising: atranslucent window to display a light at a front side of the window,wherein the light is generated from a source directed to a back side ofthe window; a first light diffuser on a back surface of the window, thefirst light diffuser operable to disperse the light at a first angle;and a second light diffuser on a front surface of the window, the secondlight diffuser operable to disperse the light at a second angle greaterthan the first angle to provide a viewing angle of the light up to about180 degrees at the front side of the window.
 22. The apparatus of claim21, wherein the translucent window is coupled to a panel of the displayassembly, and the apparatus further comprises an opaque material appliedon the back surface of the translucent window to define a discreteviewing window in a portion of the translucent window.
 23. The apparatusof claim 22, wherein the translucent window comprises a planar member,at least a portion of which is mounted in a recessed area of a surfaceof the panel.
 24. The apparatus of claim 21, wherein the translucentwindow forms a portion of a panel of the display assembly.
 25. Theapparatus of claim 21, wherein the first light diffuser comprises atranslucent coating.
 26. The apparatus of claim 21, wherein the secondlight diffuser comprises a textured surface.
 27. The apparatus of claim21, wherein the translucent window is about 50% to about 70% opaque. 28.A system comprising: a panel configured to be mounted in an electricalmodule housing, the panel comprising a window to provide a light passagefrom a first side of the panel through the window to a second side ofthe panel opposite the first side; a translucent coating applied on afirst surface of the window, the first surface nearer a light generatorthan a second surface of the window, wherein the second surface is atthe second side of the panel, wherein the translucent coating isoperable to generate a first light dispersion pattern at a first viewingangle; and a light diffuser that receives the first light dispersionpattern through the light passage and is operable to generate a secondlight dispersion pattern from the first light dispersion pattern, thesecond light dispersion pattern being generated at a second viewingangle greater than the first viewing angle, and the second viewing anglebeing up to about 180 degrees.
 29. The system of claim 28, wherein thelight diffuser is disposed on the second surface of the window toprovide the second viewing angle at the second side of the panel that isup to about 180 degrees.
 30. The system of claim 29, wherein the lightdiffuser comprises a plurality of surface irregularities on the secondsurface.
 31. The system of claim 28, wherein the translucent coating isabout 50% to about 70% opaque.
 32. The system of claim 28, wherein thewindow further comprises a border to define a portion of the window as adiscrete viewing window for the light passage.
 33. The system of claim28, wherein the border comprises an opaque material disposed on thefirst surface of the window.
 34. The system of claim 28, wherein thewindow comprises embossments formed in the window extending towards thesecond side of the panel.
 35. The system of claim 28, wherein the windowcomprises embossments formed in the window extending towards the firstside of the panel.
 36. A method comprising: providing a panel configuredfor a display assembly, the panel comprising a translucent window todisplay a light at a front side of the window when the light isgenerated from a source located at a back side of the window; dispersingthe light at a first angle through a first light diffuser positioned ata back surface of the window; dispersing the light at a second anglethrough a second light diffuser positioned at a front surface of thewindow, wherein the second angle is greater than the first angle toprovide a viewing angle of the light up to about 180 degrees at thefront side of the window.
 37. The method of claim 36, wherein dispersingthe light at the first angle through the first light diffuser comprisespassing the light through a translucent coating applied onto the frontsurface of the window.
 38. The method of claim 36, wherein dispersingthe light at the second angle comprises receiving the light dispersed atthe first angle and diverting the light to the second angle by filteringthe light through the second light diffuser, and wherein the secondlight diffuser comprises a textured surface.
 39. The method of claim 36,wherein the window is a planar member, at least a portion of which ismounted in a recessed portion of the panel.
 40. The method of claim 36,further comprising allowing light to pass through a portion of thewindow comprising a discrete viewing window defined by an opaque coatingapplied onto the window.